Gene expression profiling of Capan-1 and Pt45P1 cells treated or not with alternatively spliced tissue factor (asTF)
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ABSTRACT: The effects of alternatively spliced tissue factor (asTF) were measured by gene expression profiling of Capan-1 and Pt45P1 cells. 4 samples: Capan-1 cells +/- asTF, Pt45P1 cells +/- asTF.
Project description:Systematic mutagenesis has revealed that synonymous, non-synonymous and intronic mutations frequently alter the inclusion levels of alternatively spliced exons, suggesting that altered splicing might be a common mechanism by which mutations cause disease. However, most exons expressed in any cell are highly-included in mature mRNAs. Here, by performing deep mutagenesis of highly-included exons and by analysing the association between sequence variation and exon inclusion across the genome, we report that mutations only very rarely alter the inclusion of highly-included exons. This is true for both exonic and intronic mutations as well as for perturbations in trans. Therefore, mutations that affect splicing are not evenly distributed across the genome but are focussed in and around alternatively spliced exons with intermediate inclusion levels. These results provide a resource for prioritising synonymous and other variants as disease-causing mutations.
Project description:This SuperSeries is composed of the following subset Series: GSE22334: Induction of apoptotic processes in Capan-1 pancreatic carcinoma cells by restoration of p16INK4a expression GSE22336: UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE) is an inducer of apoptotic processes in Capan-1 pancreatic carcinoma cells: GNE silencing Refer to individual Series
Project description:Alternative splicing of mRNA diversifies the function of human proteins, with tissue- and cell-specific protein isoforms being the most difficult to validate. While transcriptomic experiments enable the detection of many alternatively spliced transcripts, it is not known if these transcripts have protein-coding potential. We recently published the PG Nexus pipeline, which facilitates high confidence validation of exons and exon-exon junctions of spliced transcripts by integrating transcriptomics and proteomics data. Using the PG Nexus, we analyzed undifferentiated human mesenchymal stem cells and compared the number of protein isoforms validated using different protein sequence database, including public online databases and RNA-seq derived databases. With significant overlaps with other databases, we identified 8,011 exons and 3,824 splice junctions with the Ensembl database. Both exonic and junction peptides were important for protein isoform validation. The Ensembl database consistently outperformed the other data sources, but predicted open reading frames from RNA-seq derived transcripts were comparable, with only 6 less splice junctions validated. Using proteotypic and isoform-specific peptides, we validated 462 protein isoforms. This number increases to 1,083 if multiple proteotypic peptides per protein are included. Multiplexing proteotypic peptides in SRM assays or similar experiments will increase the confidence and coverage of protein isoform validation experiments.
Project description:RNA splicing is a molecular mechanism to increase protein diversities acquired through the evolution while the underlieing driving forces for the phenomenon are unknown especially in terms of gene expression. Rice alternatively spliced transcript detecting microarray (ASDM) was designed and applied to differentiate the transcriptome of 4 representative organs of Oryza sativa L. cv. Ilmi including leaves, roots, panicles at 1 cm stage and young seeds at 20 days after pollination. The comparison of the data between the microarray and RNA-seq shows a ‘bell shape distribution’ and a strong co-lineation for highly expressed genes. The transcripts are classified according to the degree of organ enrichment using coefficient value (CV, the ratio of standard deviation to the mean values); highly variable (CVI), variable (CVII), and constitutive (CVIII) groups. The genes of highly variable group show the characteristics of the organs. The index of the portion of loci with alternatively spliced transcripts in a group (IAS) is designated for these CV groups and showed the higher value in the constitutive group. In addition, within a locus, a transcript with longer cds tends to be higher expressed and the spliced_intron is the most commonly found type of alternative splicing for the extended cds. Thus, constitutively expressed genes might be under evolutionary pressure toward alternative splicing that might have a longer cds. These data show that less resource consuming and better designed microarray might be a niche technology to test the transcriptome analysis including alternatively spliced transcripts in plants.